Dresden 2017 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 81: Transport: Spintronics, Spincalorics and Magnetotransport (jointly with DS, HL, MA)

HL 81.6: Vortrag

Freitag, 24. März 2017, 10:45–11:00, HSZ 03

Emergent magnetic ordering in transition metal atomic contacts — •Martin Keller, Florian Strigl, Elke Scheer und Torsten Pietsch — Department of Physics, University of Konstanz, 78457 Konstanz, Germany

MD simulations and DFT calculations predict the development of local magnetic order at reduced dimensions in some paramagnetic transition metals (Pt, Pd, Ir), especially in atomic configurations [1,2,3]. This unusual property allows us to investigate the influence of the local magnetic properties on the conductance of atomic contacts without the effect of magnetic leads. Therefore atomic contacts of these metals are a model system to understand the origin of magnetoconductance and the role of spin-polarization of the conduction electrons. Herein we discuss recent results of Pt, Pd and Ir in the context of a microscopic model that successfully describes the observed magnetoconductance signature in these atomic contacts and chains [4]. Additionally, electronic transport spectroscopy is used to evaluate magnetic excitations in the electronic system of the contact, i.e. the presence of i) a zero-bias anomaly which is described by Kondo physics and ii) conductance fluctuations in the atomic contact, which indicate the formation of a magnetically ordered state. We will compare the three transition metals with respect to their different electronic structure and the role of spin-orbit coupling in the contacts.

[1] Phys. Rev. Lett. 92, 057201 (2004)

[2] Phys. Rev. B 78, 014423 (2008)

[3] Phys. Rev. B 81, 054433 (2010)

[4] Nature Comm. 6, 6172 (2015); Phys. Rev. B 94, 144431 (2016)